With the recent increase in concern about environmental issues, the demand for fuel efficient automobiles has been increasing. There is also a need for rubber compositions for automotive tires having higher fuel economy. For example, rubber compositions containing conjugated diene polymers such as polybutadiene or butadiene-styrene copolymers and filler such as carbon black or silica are used in automotive tires.
Patent Literature 1, for example, proposes a method for improving fuel economy by using a diene rubber (modified rubber) that has been modified with an organosilicon compound containing an amino group and an alkoxy group. Although such conventional techniques improve fuel economy, it is also important from economic and safety standpoints to ensure sufficient abrasion resistance and tensile properties (rubber tensile strength). In the conventional techniques, unfortunately, the abrasion resistance, which is in a trade-off relationship with fuel economy, is insufficient to solve this challenge, and rubber chipping can also be caused. Thus, it is difficult to simultaneously improve fuel economy, rubber tensile strength, and abrasion resistance.
Patent Literature 2 proposes a method for improving rubber tensile strength, abrasion resistance, and other properties by the use of a hydrogenated diene polymer.